MTN worst data provider!!!

MTN is the worst data provider!! I would NOT recommend anyone to take a data contract EVER at MTN!!! My 24 month data contract came to an end on the 12th of August, never did I receive any communication beforehand that I need to upgrade or cancel otherwise they will continue with a Month to month contract, at more than double the contract price!!! Only on the 12th was I informed that I am now on a month to month contract for R510, my invoice though is R580?? On the 12th of August after receiving the sms I phoned them and told them I am not interested in this month to month contract and they apparently cancelled it. However I still owe the R580 now?? Trying to call the customer care... But keep getting service error so cannot get through. I have emailed them and requested the invoice to be reversed as I cancelled it however I am not getting any decent answer or joy from Mtn. VERY VERY DISAPPOINTED. To get a contract is quick but once the contract ends THEY decide to put you on a month to month whether you are interested or not and to get that cancelled is a huge mission.